The ability to successfully regulate emotions is among the most critical of human capacities. Basic research in affective neuroscience has begun to elucidate the cognitive processes which support this vital ability, attesting in particula to the efficacy of two major forms of emotion regulation, attentional deployment (AD) and cognitive reappraisal (CR). AD and CR are thought to operate through distinct cognitive mechanisms, differing both in (1) when they impact the temporal trajectory of emotion generation, and (2) which neural systems they engage. Critically, recent behavioral research has shown that AD and CR are differentially affected by the intensity of the emotion to be regulated, with CR - but not AD - becoming less effective under high levels of emotional load. The mechanisms underlying this differential impact of emotional load on AD and CR remain unclear. The broad, long-term objective of this proposal is to use a neurobiologically informed framework to account for the differential effect of emotional load on AD and CR by elucidating key differences in their temporal dynamics and patterns of neural engagement. More specifically, we propose to use electroencephalography (EEG) and functional magnetic resonance imaging (fMRI) to examine AD and CR under differing levels of emotional load. We hypothesize that (1a) AD will attenuate an electrocortical index of emotional stimulus processing (the late positive potential; LPP) at an early phase, but that CR will do so at a later phase, and importantly, (1b) the early attenuation of the LPP by AD will remain consistent across varying levels of emotional load, but the late attenuation by CR will weaken under high levels of emotional load. Second, we hypothesize that (2a) AD will recruit prefrontal and parietal regions involved in attentional control, whereas CR will recruit lateral and medial prefrontal brain region which have been associated with cognitive control and with affective meaning processing, and crucially, (2b) the modulation of amygdala activity via attentional brain regions in AD will be consistent across varying levels of emotional load, but the modulation of amygdala activity via affective-meaning processing regions in CR will vary as a function of emotional load (with no modulation under high emotional load). Our proposed research will help us to understand why certain regulation strategies seem to break down and become ineffective under high levels of emotional load, and may suggest new interventions for high-risk individuals based on the notion that, in order to optimize their overall utility, regulation strategies may need to be flexibly deployed according to the unique emotional demands of the situation.